<?php

namespace App\Services;

use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;
use RuntimeException;

class WeChatMiniProgramService
{
    public function getAccessToken(): string
    {
        $appId = config('services.wechat.mini_program.app_id');
        $secret = config('services.wechat.mini_program.secret');

        if (! $appId || ! $secret) {
            throw new RuntimeException('微信小程序 AppID/Secret 未配置');
        }

        return Cache::remember('wechat_miniapp_access_token', 7000, function () use ($appId, $secret) {
            $response = Http::timeout(10)->get('https://api.weixin.qq.com/cgi-bin/token', [
                'grant_type' => 'client_credential',
                'appid' => $appId,
                'secret' => $secret,
            ]);

            $payload = $response->json();
            if (! is_array($payload) || ! empty($payload['errcode'])) {
                throw new RuntimeException((string) ($payload['errmsg'] ?? '获取微信 access_token 失败'));
            }

            $token = $payload['access_token'] ?? null;
            if (! is_string($token) || $token === '') {
                throw new RuntimeException('微信 access_token 响应异常');
            }

            return $token;
        });
    }

    public function getUnlimitedWxaCode(string $page, string $scene): string
    {
        $scene = trim($scene);
        if ($scene === '') {
            throw new RuntimeException('签到码不能为空');
        }
        if (strlen($scene) > 32) {
            throw new RuntimeException('签到码不能超过 32 个字符');
        }

        $token = $this->getAccessToken();
        $response = Http::timeout(20)
            ->withHeaders(['Content-Type' => 'application/json'])
            ->post("https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token={$token}", [
                'scene' => $scene,
                'page' => ltrim($page, '/'),
                'check_path' => false,
                'env_version' => config('services.wechat.mini_program.env_version', 'develop'),
                'width' => 430,
            ]);

        $contentType = (string) $response->header('Content-Type');
        if (str_contains($contentType, 'json') || str_starts_with(trim($response->body()), '{')) {
            $payload = $response->json();
            if (is_array($payload) && ! empty($payload['errcode'])) {
                throw new RuntimeException((string) ($payload['errmsg'] ?? '生成小程序码失败'));
            }
        }

        $body = $response->body();
        if ($body === '') {
            throw new RuntimeException('生成小程序码失败：空响应');
        }

        return $body;
    }

    /**
     * @return array{openid: string, unionid?: string, session_key: string}
     */
    public function codeToSession(string $code): array
    {
        $appId = config('services.wechat.mini_program.app_id');
        $secret = config('services.wechat.mini_program.secret');

        if (! $appId || ! $secret) {
            throw new RuntimeException('微信小程序 AppID/Secret 未配置');
        }

        $response = Http::timeout(10)->get('https://api.weixin.qq.com/sns/jscode2session', [
            'appid' => $appId,
            'secret' => $secret,
            'js_code' => $code,
            'grant_type' => 'authorization_code',
        ]);

        $payload = $response->json();
        if (! is_array($payload)) {
            throw new RuntimeException('微信登录响应异常');
        }

        if (! empty($payload['errcode'])) {
            throw new RuntimeException((string) ($payload['errmsg'] ?? '微信登录失败'));
        }

        if (empty($payload['openid'])) {
            throw new RuntimeException('微信登录未返回 openid');
        }

        return [
            'openid' => (string) $payload['openid'],
            'unionid' => isset($payload['unionid']) ? (string) $payload['unionid'] : null,
            'session_key' => (string) ($payload['session_key'] ?? ''),
        ];
    }
}